Выбор цены через select и прибавление к сумме в корзине

[silverberg]

Добрый день!

Как нижеприведенный код для radiobuttons изменить под select. Спасибо!

Исходные строки кода с радиокнопками:

<span id="sub_price" style="display: none;">{$cart->total_price}</span>
<span id="subtotal_price"></span>&nbsp;{$currency->sign}

... радиокнопки:

<input type="radio"  name="delivery_id"onclick="select_delivery_method({$delivery->id});" value="{$delivery->id}" {if $delivery_id==$delivery->id}checked{elseif $delivery@first}checked{/if} id="deliveries_{$delivery->id}">
<label for="deliveries_{$delivery->id}">{$delivery->name} <span id="delivery_price_{$delivery->id}">{$delivery->price}</span> &nbsp;{$currency->sign}</label>

<script>
      function select_delivery_method(method_id)
      {
        radiobuttons = document.getElementsByName('delivery_id');
        for(var i=0;i<radiobuttons.length;i++)
        {
          if(radiobuttons[i].value == method_id)
          {
            radiobuttons[i].checked = 1;
          }
        }
      var subtotal = parseFloat(document.getElementById('sub_price').innerHTML);
      var delivery = 0;
      if(document.getElementById('delivery_price_'+method_id))
        delivery = parseFloat(document.getElementById('delivery_price_'+method_id).innerHTML);
      total = subtotal+delivery;
         document.getElementById('subtotal_price').innerHTML = total;                             
      }
    </script>
    <script>
      select_delivery_method(1);
    </script>

Код select.

<select name="delivery_id" onclick="select_delivery_method({$delivery->id});">
<option value="{$delivery->id}">{$delivery->name}
<span id="delivery_price_{$delivery->id}">{$delivery->price}</span>&nbsp;{$currency->sign}
</option>
</select>